Starting to make ok power in my vl now but traction is a thing of the past.
Its not so bad on the street, some what fun really but for the times when i need it to hook up id like to know what size semi slicks i can run.
At this stage the car has stock tubbs and stock length diff, im running ame 20inch rims and can only just fit 225s on them so hooking up and looking good wont happen.
What i want to know is if i go to powercruise or something and want to hook up what is my best option for good rubber In a semi slick?
I can run 15s 16s 17s 18s whatever cause ill get rims and rubber

yeah I think the VZ ceptor off the utes is a 15x8, but mine were 195 each to get made, new bands, offset to suit VL. I'll be running a 235 on these, I have used a 255 - but I would of probably needed to raise the rear a bit or used a stiffer spring - they do fit however.

i would also like to know this, i have a vy ss with the standard 18's and is slightly lowered. Wheel arch is just above the tyre, i purchased micky thompson 235/40r18 street comps and they are useless.

I thought monaros ran a 15x4 hence the name space saver. I also thought they were rated at 80 kph and can be use on a track

Yes and yes. However the reason why you'll see some people running space savers (though not that common now due to the cheaper prices of drag wheels) is due to them being strong enough when going in a straight line. It's when they're corning that they are under stress and likely to crack.